Neuraminidase (NA)
and hemagglutinin (HA) are major membrane glycoproteins found on the surface of
influenza virus. Hemagglutinin binds to the sialic acid-containing receptors on
the surface of host cells during initial infection and at the end of an infectious
cycle. Hemagglutinin also plays a major role in the determination of host range
restriction and virulence. As a class I viral fusion protein, hemagglutinin is
responsible for penetration of the virus into the cell cytoplasm by mediating
the fusion of the membrane of the endocytosed virus particle with the endosomal
membrane. Binds to sialic acid-containing receptors on the cell surface,
bringing about the attachment of the virus particle to the cell. This
attachment induces virion internalization either through clathrin-dependent
endocytosis or through clathrin- and caveolin-independent pathway. Plays a
major role in the determination of host range restriction and virulence. Class
I viral fusion protein. Responsible for penetration of the virus into the cell
cytoplasm by mediating the fusion of the membrane of the endocytosed virus
particle with the endosomal membrane. Low pH in endosomes induces an
irreversible conformational change in HA2, releasing the fusion hydrophobic
peptide. Several trimers are required to form a competent fusion pore.
中文
